New South Wales coach Laurie Daley is a relieved man after scans cleared his State of Origin captain Paul Gallen of a serious knee injury.

Daley admitted concern when the talismanic forward went down just three minutes into Cronulla's upset win over Newcastle on Sunday and spent the rest of the game with a brace on his knee and a scowl on his face.

But, with State of Origin I less than a month away, scans on Monday gave Daley, Gallen and the Blues the best possible news.

They confirmed a medial ligament strain in his right knee, rather than a tear which would have sidelined the 31-year-old for up to six weeks.

Cronulla said Gallen was unlikely to be fit to play the Wests Tigers on Friday night but, while no time frame had yet been given for a return, he was not expected to be sidelined for an extended period.

Daley was heartened by Gallen's comments that he still hoped to play on Friday and confident he was too professional to endanger his recovery by returning too soon.

"Given that Origin is four weeks away, if he's thinking about playing on Friday night I don't think there's any worries of him not being there game one," Daley said on Monday.

"Obviously he's the captain and has been an inspirational part of the New South Wales team over the past few seasons.

"It was great to receive that news that morning. It wasn't great yesterday watching him go down and seeing him sitting on the sideline with the brace on his leg.

"But it's not as serious as we first thought so it's good news."

Daley said he did not believe the injury would hinder Gallen's preparation as the Blues look to stop Queensland from an eighth-straight series win.

Last year Gallen injured his posterior cruciate ligament in the lead-up to game one of the Origin series, and he was in doubt right up until the final days before the match.

"I don't think (it will affect his preparation)," he said.

"He's a professional and he'll look after himself.

"And if he's not right to play he certainly won't play.

"Being the player that he is, he puts his club first and so he should."